Search results for "Genome"
showing 10 items of 1913 documents
Characterization and chromosomal localization of the chicken avidin gene family
2000
Chicken avidin is a biotin-binding protein expressed under inflammation in several chicken tissues and in the oviduct after progesterone induction. The gene encoding avidin belongs to a family that has been shown to include multiple genes homologous to each other. The screening and chromosomal localization studies performed to reveal the structure and organization of the complete avidin gene family is described. The avidin gene family is arranged in a single cluster within a 27-kb genomic region. The cluster is located on the sex chromosome Z on band q21. The organization of the genes was determined and two novel avidin-related genes, AVR6 and AVR7, were cloned and sequenced.
Mutational fitness effects in RNA and single-stranded DNA viruses: common patterns revealed by site-directed mutagenesis studies
2010
The fitness effects of mutations are central to evolution, yet have begun to be characterized in detail only recently. Site-directed mutagenesis is a powerful tool for achieving this goal, which is particularly suited for viruses because of their small genomes. Here, I discuss the evolutionary relevance of mutational fitness effects and critically review previous site-directed mutagenesis studies. The effects of single-nucleotide substitutions are standardized and compared for five RNA or single-stranded DNA viruses infecting bacteria, plants or animals. All viruses examined show very low tolerance to mutation when compared with cellular organisms. Moreover, for non-lethal mutations, the me…
Arabidopsis thalianagenes contributing to differences in the outcome of infection with generalist and specialist strains ofTurnip mosaic virusidentif…
2020
AbstractPathogens can be classified as generalists or specialists depending on their host breadth. While generalists are able to successfully infect a wide variety of host species, the host range of specialists is limited to a few related species. Even though generalists seem to gain an advantage due to their wide host range, they usually pay a cost in terms of fitness within each host species (i.e., the jack-of-all trades, master of none). On the contrary, specialists have high fitness within their own host. A highly relevant yet poorly explored question is whether generalist and specialist viruses differ in the way they interact with their host’s gene expression networks. To identify host…
A mammalian gene evolved from the integrase domain of an LTR retrotransposon.
2001
FIG. 1.—Summary of the structure and coding sequence of the human Gin-1 gene. Sequences of human cDNAs with accession numbers XMp003947.2 (a putative full-length cDNA), BE502574, AW173201.1, AW950418.1, AI631948.1, and AA766836.1 were used to deduce and confirm these data. The full-length protein is 522 amino acids long. The Gin-1 coding region spans nucleotides 36153–15345 in the genomic clone NTp002663.4. Arrowheads and the numbers above them, respectively, indicate the positions and lengths of introns. Several Alu repeats were detected within the two largest introns. Bold letters indicate the region homologous to the most conserved part of the IN domain, detailed in figure 2 and used to …
Genome-Based Examination of Chlorophyll and Carotenoid Biosynthesis in Chlamydomonas reinhardtii
2005
Abstract The unicellular green alga Chlamydomonas reinhardtii is a particularly important model organism for the study of photosynthesis since this alga can grow heterotrophically, and mutants in photosynthesis are therefore conditional rather than lethal. The recently developed tools for genomic analyses of this organism have allowed us to identify most of the genes required for chlorophyll and carotenoid biosynthesis and to examine their phylogenetic relationships with homologous genes from vascular plants, other algae, and cyanobacteria. Comparative genome analyses revealed some intriguing features associated with pigment biosynthesis in C. reinhardtii; in some cases, there are additiona…
Point Mutation Rate of Bacteriophage ΦX174
2009
Abstract The point mutation rate of phage ΦX174 was determined using the fluctuation test. After identifying the genetic changes associated with the selected phenotype, we obtained an estimate of 1.0 × 10−6 substitutions per base per round of copying, which is consistent with Drake's rule (0.003 mutations per genome per round of copying in DNA-based microorganisms).
Hutchinson Gilford Progeria Syndrome: A Therapeutic Approach via Adenoviral Delivery of CRISPR/cas Genome Editing System
2015
Hutchinson-Gilford Progeria Syndrome (HGPS) is a rare human genetic disease caused by mutations in the LMNA gene. LMNA codes for structural components of the nuclear lamina. Alterations of nuclear lamina lead to a very variable class of diseases known as laminopathies. In detail, HGPS manifests a severe premature ageing phenotype due to the accumulation of a dominant negative form of lamin-A called progerin. With current treatments, the life expectancy of HGPS patients does not exceed their second decade. Death is usually due to cardiovascular complications. Recently, a new technology for mammals in vivo gene editing has been developed: the clustered regularly interspaced short palindromic …
Holocene selection for variants associated with cognitive ability: Comparing ancient and modern genomes
2017
ABSTRACTHuman populations living in Eurasia during the Holocene experienced considerable microevolutionary change. It has been predicted that the transition of Holocene populations into agrarianism and urbanization brought about culture-gene coevolution that favoured via directional selection genetic variants associated with higher general cognitive ability (GCA). To examine whether GCA might have risen during the Holocene, we compare a sample of 99 ancient Eurasian genomes (ranging from 4.56 to 1.21 kyr BP) with a sample of 503 modern European genomes, using three different cognitive polygenic scores. Significant differences favouring the modern genomes were found for all three polygenic s…
Successful Replication of GWAS Hits for Multiple Sclerosis in 10,000 Germans Using the Exome Array
2015
Genome-wide association studies (GWAS) successfully identified various chromosomal regions to be associated with multiple sclerosis (MS). The primary aim of this study was to replicate reported associations from GWAS using an exome array in a large German study. German MS cases (n = 4,476) and German controls (n = 5,714) were genotyped using the Illumina HumanExome v1-Chip. Genotype calling was performed with the Illumina Genome Studio(TM) Genotyping Module, followed by zCall. Single-nucleotide polymorphisms (SNPs) in seven regions outside the human leukocyte antigen (HLA) region showed genome-wide significant associations with MS (P values < 5 × 10(-8) ). These associations have been repor…
Viral mutation and substitution: units and levels.
2011
Viruses evolve within a hierarchy of organisational levels, from cells to host species. We discuss how these nested population structures complicate the meaning and interpretation of two apparently simple evolutionary concepts: mutation rate and substitution rate. We discuss the units in which these fundamental processes should be measured, and explore why, even for the same virus, mutation and substitution can occur at very different tempos at different biological levels. In addition, we explore the ability of whole genome evolutionary analyses to distinguish between natural selection and other population genetic processes. A better understanding of the complexities underlying the molecula…